Toothbrush

ABSTRACT

A toothbrush having a brush head made from plastic and vertical individual bristles made from plastic embedded into the brush head which are disposed at small separations with respect to each other, is distinguished in that, on the bristle head portion having bristles, approximately 400 to 800 individual bristles per cm 2  are disposed and the overall height of the toothbrush comprising the free length of the individual bristles and the thickness of the brush head assumes a value between 6.5 and 11 mm.

BACKGROUND OF THE INVENTION

The invention concerns a toothbrush having a brush head made fromplastic and individual plastic bristles vertically embedded into thebrush head disposed at a small separations with respect to each other.

Toothbrushes of this type are known in the art (WO 96/27 308). Incontrast to conventional toothbrushes with which the bristles arecollected into individual bundles and a plurality of bundles are mountedto the brush head, the above mentioned toothbrushes have the advantagethat the ends of the bristles which are substantially active duringcleaning are evenly distributed over the entire brush surface so thatthe medically recommended cleaning method from red to white, that is tosay a substantially vertical guiding of the brush with an overlappingslightly pivoting motion, leads to cleaning (of the teeth) and massaging(of the gums) in the entire region swept over by the bristle stock. Withtoothbrushes having the conventional bundle stock, certain parts of thegums and or teeth remain untreated. One had tried to counteract thisproblem by disposing the bristles in a non-parallel fashion within thebundle so that they were spread apart. This had however, duringcleaning, the consequence that the bristles stood at differing angleswith respect to the surface being cleaned. This can cause injury to thegums. In addition, the tilted bristles are more active in thetransitional region towards the side of the bristle than at theirrounded bristle ends. Since such transition regions can be edged if thebristles are not perfectly rounded, injury to the gums or fine lesionsof the enamel can result.

Among other factors, the flexural strength of the bristles is importantfor the effectiveness of the toothbrush. In a bundle, this issubstantially determined by the length of the bundle and the packingdensity of the bristles in the bundle as well as by the diameter of theindividual bristles, wherein the latter has the smallest influence ofall since the bristles in the bundle support one another so that theflexural strength of the bundle is many times larger than that of theindividual bristles. In the above mentioned conventional toothbrush (WO96/27 308) having individually standing bristles, the flexural strengthis additionally influenced by the separation of the bristles fromanother. Due to this separation, the influence of the bristle diameteris more prominent than in bundles. The flexural strength can thereby bevaried in steps finer than those standard with conventionaltoothbrushes: namely, “soft”, “middle” and “hard”. The reduced embeddedlength of the individual bristles compared to bundles allows the heightof the brush head to be reduced.

Dentistry has pointed out that the care and cleaning of the molar teeth,in particular on the outer side of the teeth (distal), is substantiallyworse than in the front tooth region. This has to do with the pooraccessibility of the molars, the frequently confined space of the distalregion which, given abnormalities in tooth formation, can assume seriousdimensions, and the frequent increased sensitivity and irritation in thedistal region of the molars which, depending on how the toothbrush isintroduced, can even induce vomiting. Even the red-white cleaning methodrecommended by dentists, can not be properly carried out in the molarregion due to the confined space. The increased pressure also causesinjury to the gums and lesions in the enamel in this region.

It is the underlying purpose of the invention to create a toothbrushwhich also permits easy application in the molar region allowing thered-white method to be carried out and particular facilitating equallysatisfactory cleaning of the molar regions in the distal area.

SUMMARY OF THE INVENTION

Departing from the toothbrush in accordance of the precharacterizingpart of claim 1 WO 96/27 308, this purpose is achieved in accordancewith the invention in that the portion of the brush head having bristlescontains approximately 400 to 800 individual bristles per cm² and theoverall height of the toothbrush resulting from the free length of theindividual bristles and the thickness of the brush head assumes a valuebetween 6.5 and 11 mm.

The toothbrush in accordance with the invention is initiallydistinguished by an extremely small height formed from the free bristlelength and the thickness of the brush head. This height assumes valuesbetween 6.5 and 11 mm, whereas the conventional toothbrushes extend upto 20 mm. Due to this flat construction, it is also easy to clean thedistal region of the molars and the red-white method can be utilized inthis location with the applied pressure being completely determined bythe user, since even the inner sides of the cheeks no longer exerciseany pressure on the toothbrush. The plurality of narrowly separatedindividual bristles also allows for adjustment of the flexural strengthdespite the reduced length of the individual bristles in a user specificmanner.

Flat toothbrushes have been proposed (DE 93 03 339 U1) with which thehorizontal length of conventional brushes having bundles has simply beenshorted. This, however, leads to an increase in the stiffness of theconventional toothbrush having bristle bundles. This was, in fact, thespecific intent of this prior art in order to achieve improvedmechanical friction. Precisely this is, however, undesirable for medicalreasons.

Another conventional embodiment (EP 0 060 592) led to the same negativeeffects. In this embodiment, the individual bristles are disposed atnarrow separation from each other and held in a frame-like brush headstructure. In this case, the flexural strength is even larger than forbristle bundles, since the individual bristles support each other alongtheir entire length.

An additional conventional toothbrush (DE 296 00 139 U1) has microfibersintroduced onto the brush head proximate conventional bristle bundles.These microfibers are of low flexural strength and therefore extremelysoft so that they cannot exercise any mechanical effect on the toothcoating. They have, at most, a polishing effect. Such microfibers canalso not be directly attached to the brush head due to their extremelysmall diameter.

The configuration in accordance with the invention is equally effectiveboth for manual toothbrushes having a handle attached to a brush head aswell as for electrically driven toothbrushes with which the brush headis mounted onto a drive.

It is preferred when the free length of the individual bristles assumesa value between 5 and 9.5 mm and the thickness of the brush head a valuebetween 1.5 and 3.0 mm. The low thickness of the brush head isparticularly facilitated by the fact that the individual bristles mustonly be embedded over a small length in the brush head plastic in orderto achieve the necessary pull-out strength.

The configuration in accordance with the invention further allows ashape to be given to the active brush surface, wherein the free ends ofthe individual bristles lie on a constant or varying curved envelopingsurface the separation of which from the brush head surface varies by upto 3 mm.

This topography guarantees that not only the surfaces of the teeth butalso the inter-dental regions are reached and cleaned by the bristles.In the vicinity of the gums, special massage effects result with thelonger bristles being deflected when pressed to act along the outerportion of the bristles and cause a rubbing massage motion. The shorterbristles are active at their ends.

An additional variation for the flexural strength can be achieved whenthe diameter of the individual bristles lies between 0.095 and 0.225 mmwith the chosen effective diameter being smaller, the smaller the freelength of the individual bristles.

It is thereby preferred, with a free length for the individual bristlesof between 5 to 7 mm, for their diameter to be chosen between 0.095 and0.175 and, with a free length of 7 to 9.5 mm, to have a diameter between0.125 and 0.225 mm.

A preferred embodiment of the toothbrush in accordance with theinvention is distinguished by a height of the toothbrush ofapproximately 8.5 mm with a free length of the individual bristles of 7mm and a thickness of the brush head of 1.5 mm and with approximately600 bristles per cm².

In an additional advantageous configuration of the invention, theindividual bristles are embedded into the brush head by injectionmolding their attachment sided ends with the plastic of the brush head.

This method for attaching the individual bristles leads to the largestpossible pull-out strength for the shortest possible embedded length.The individual bristles in the vicinity of their attachment arecompletely surrounded by the plastic of the brush head so that a gapfree surface is guaranteed. This is desirable for hygienic reasons.

The configuration in accordance with the invention also allows for thebrush head to have a convex bulged surface at its side facing thebristles with the individual bristles being approximately perpendicularto the surface.

In this configuration, the ends of the bristles, to the extent that theyare of equal length, lie on a corresponding convex enveloping surface.This facilitates, in connection with the red-white method with which thetoothbrush is normally slightly pivoted, a better engagement by thebristle ends. In conventional bundle toothbrushes, one had attempted toachieve the same effect by having the bundle be perpendicular to thesurface only along the longitudinal middle axis of the brush head andtilted in an outer direction with associated substantial shortening ofthe outer lying bundles. This tilted configuration causes differingbrushing and cleaning action for the individual bundles. In addition,the slanted configuration of the bristles is associated with the dangerthat they fold over in opposition to the cleaning direction and act as aspear. The convex configuration of the brush head within the frameworkof the invention is facilitated, without a substantial increase in theheight, by the small thickness of the brush head.

In this embodiment, the back of the brush head can simultaneously beconcave bulged so that the brush head has approximately the samethickness along its entire length without having the brush headexcessively stiffened by this shape. In this embodiment, the individualbristles disposed perpendicular to the surface are preferentially ofequal length.

The attachment sided ends of the individual bristles are preferentiallyembedded by an amount which is less than 10 times the diameter of thebristle. The embedded length assumes values, with the above mentioneddiameter range of 0.125 to 0.225, of not more than 1.25 to 2.25 mm.

The invention is described below in connection with embodiments shown inthe drawings.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 shows a plan view of the bristle stock of a toothbrush;

FIG. 2 shows a side view of a toothbrush in accordance with FIG. 1;

FIG. 3 shows an enlarged section of a longitudinal cut in the vicinityof the brush head;

FIG. 4 shows a plan view of the illustration in accordance with FIG. 3;and

FIG. 5 shows a cross section through another embodiment of the brushhead.

DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 2 show a toothbrush 1 used for manual applications. It has ahandle 2 and a preferentially flexible neck 3 as well as a brush head 4having bristle stock 5. The bristle stock 5 consists essentially ofindividually standing bristles disposed at small separations from eachother, as can be seen from FIGS. 3 and 4. The individual bristles 5 areanchored at their ends 7 within the brush head 4. For example, theindividual bristles have enlargements 8 molded at their ends 7 withwhich they are injection molded with and anchored in the plastic of thebrush head 4.

The bristles 6 have a diameter between 0.095 and 0.225 mm and a freelength “1” between 5 to 9.5 mm. The diameter is smaller, the shorter thefree length “1”. Practical experiments have shown the followingconfiguration to be advantageous: diameter 0.095 to 0.175 mm with a freelength “1” of 5 to 7 mm and diameter 0.125 to 0.225 mm with a freelength of 7 to 9.5 mm.

The overall height of the toothbrush in the vicinity of the brush headis between 6.5 and 11 mm, wherein the thickness “d” of the brush head isbetween 1.5 and 3.0 mm. The embedded depth “a” of the individualbristles assume values between 0.2 and 0.8 mm, preferentiallyapproximately 0.4 mm. The separation of the individual bristles 6 withrespect to each other is preferentially chosen in such a fashion thatthere are approximately 600 bristles per cm² .

In the embodiment in accordance with FIG. 5, the brush head has abulging cross section so that the ends of the individual bristles 6 lieon a correspondingly bulged enveloping surface. This enveloping surfacecan also be waved or stepped through differing lengths of the individualbristles 6. The individual bristles are perpendicular to the surface ofthe brush head 4.

What is claimed is:
 1. A toothbrush comprising: a brush head made fromplastic, said brush head having a bristle surface; and individualstanding bristles made from plastic, said bristles embedded into saidbrush head at said bristle surface, said bristles having a density ofbetween 400 and 800 bristles per cm² at said bristle surface, wherein anoverall height of the toothbrush is equal to a free length of saidbristles plus a thickness of said brush head, said overall height beinggreater than 6.5 mm and less than 11 mm.
 2. The toothbrush of claim 1,wherein said free length of said bristles is between 5 and 9.5 mm andsaid thickness of said brush head is between 1.5 and 3.0 mm.
 3. Thetoothbrush of claim 1, wherein free ends of said bristles lie on anenvelope surface, said envelope surface having one of a constant and avarying curvature, said envelope surface having a range of separationsfrom said bristle surface of less than 3 mm.
 4. The toothbrush of claim1, wherein said bristles have a diameter of between 0.095 and 0.225 mm,wherein a chosen effective diameter is smaller, the smaller said freelength of said bristles.
 5. The toothbrush of claim 4, wherein said freelength of said bristles is between 5 and 7 mm, and said diameter isbetween 0.095 and 0.175 mm.
 6. The toothbrush of claim 4, wherein saidfree length of said bristles is between 7 and 9.5 mm and said diameteris between 0.125 and 0.225 mm.
 7. The toothbrush of claim 1, whereinsaid overall height is approximately 8.5 mm, said free length isapproximately 7 mm, and said thickness of said brush head isapproximately 1.5 mm.
 8. The toothbrush of claim 1, wherein said densityis approximately 600 bristles per cm².
 9. The toothbrush of claim 1,wherein said bristles are embedded in said plastic of said brush headusing an extrusion procedure by injection molding said brush headplastic around bristle attachment ends.
 10. The toothbrush of claim 1,wherein said bristle surface has a convex bulging shape, said bristlesbeing approximately perpendicular to said bristle surface.
 11. Thetoothbrush of claim 10, wherein said brush head thickness isapproximately constant, said brush head being curved in a convexfashioned at said bristle surface and in a concave manner at a backsurface opposite said bristle surface.
 12. The toothbrush of claim 10,wherein said individual bristles have a constant length.
 13. Thetoothbrush of claim 1, wherein said bristles are embedded at attachmentends along a length which is less than 10 times a diameter of anindividual bristle.